Morphometry and Flood in Small Drainage Basin: Case Study of Mayogwoi River Basin in Jalingo, Taraba State Nigeria

Abstract

Drainage basin morphometric information is very important in any undertaking to control incidence of flooding in an area. In the present study, morphometrc analysis using remote sensing and GIS techniques have been carried out to examine the flood potentials of the Mayogwoi river basin. The Mayogwoi basin is a small basin. The pattern of this basin is dendritic. The values of bifurcation ratio (2.45), circularity ratio (0.64), elongation ratio (0.66) and form factor (0.35) indicates that the basin is moderately circular and somewhat elongated. The length of overland flow of the basin is 1.25, indicating matured topography and low surface runoff in the study area. The low drainage density (0.4 km/km2) and low stream frequency (0.11) is indicative of low relief, low surface flow, high infiltration and consequently low flood potentials of the basin. The basin has a low relief ratio (0.074) and low relative relief (2.38) indicating low relief and gentle slope. The result of the findings also shows that the basin has a short basin length of 32.2 km indicative of higher chances of the basin been flooded after heavy rainfall of short duration. Consequently, the result shows that there will hardly be enough water supplies to support large scale water resource development prospects particularly irrigation and hydropower project in the basin except with intensive development of land and water resources of the basin. Thus, high intensity of rainfall is required for the generation of flash flood in the drainage basin because of its relatively small basin size. The morphometric parameters of the basin therefore suggest low to moderate flash floods chances and high potential of groundwater aquifers recharge. Thus, heavy rainfall is the most important flash flood - causing factor, followed by morphometric characteristics and land uses in the basin.